Eccentric rotary engines are rotary engines in which motion is imported to a shaft by a rotor that is eccentric to the shaft. A leading eccentric rotor engine is the “Wankel” engine, early examples of which are disclosed in U.S. Pat. No. 2,988,065, granted Jun. 13, 1961, to Felix Wankel and Ernst Hoeppner. A popular type of this motor includes a three-lobe rotor which is rotatable inside a rotor chamber formed in a housing or stator. The rotor is generally in the shape of a triangle having three lobes. Seals carried by apex portions of the lobes slide along an inner peripheral surface of the rotor cavity which is generally referred to as being epitrochoidal or trochoidal in shape. Side seals that are embedded in the sides of the rotor make sliding engagement with the inner surfaces of the sidewalls of the rotor chamber. Corner seals are embedded in the corner regions of the rotor where the side seals substantially meet the apex seals. The rotor cavity has intake and exhaust ports. As the rotor rotates within the rotor cavity, the side faces of the rotor cooperate with the walls of the cavity to define intake, compression, and exhaust chambers, so that during rotation of the rotor, the four phases of intake, compression, expansion, and exhaust are provided during each revolution of the rotor.
U.S. Pat. No. 3,876,346, granted Apr. 8, 1975, to David G. Kokochak shows a corner seal having a square bottom apex seal slot. The shortest radial dimension is at the lower corners of the apex seal slot or the bottom meets the sidewalls of the slot. This radius dimension increases from the corner regions to the center of the bottom of the apex seal recess. This construction of the corner seal makes the corner seal susceptible to breaking at the corner regions of the apex seal slot.
Known corner seals are susceptible to breakage at a frequent enough rate that there is a need to address the problem and provide an improved corner seal having a longer use life. It is the primary object of the present invention to address this problem and provide an improved corner seal. It is an object of the present invention to provide a corner seal that performs its sealing function effectively and which is durable and has a longer use life than conventional corner seals. Another object of the invention is to provide an improved combination of an apex seal and corner seals at its two ends.